Carburetor



March 10, 1931. v C, w, SPOHR 1,795,319

-cARBUREToR Filed oci. 14. 1926 ar/ WS/Do/zr '521W Zz 6 Wmv-M9 PatentedMar. io, 1931 UNITED wSTATES PATENT OFFICE CARL W. SPOHB,

TRUSTEE,

cARBUnn'ron Application iled October 14, 1926. Serial No. 141,448.

My invention relates generally to carburetors. It relates moreparticularly to the type of carburetors in whichthe vacuum 1nduced inthe carburetor itself is employed to draw the fuel from the fuel supplytank, which may be located at a levellower than that of the carburetor.

It is an object of my invention to provide an improved carburetor inwhich the fuel supply is more accurately and closely regulated, in whichmercury is employed as a medium liquid fuel to the float chamber, and toprovide means for preventin the mercury from being spilled from the caruretor.

Other objects will appear from the following description, referencebeing had to the accompanying drawings in which,

Figure 1 is a central vertical section of my improved carburetor. Y

Figure 2 is a diagrammatic iew of an automobile chassis and engineshowing how lmy im roved carburetor is installed on an automo ile.

In Figure 2 the fuel supply tank 3 is connected by the usual tube 4 tothe carburetor designated generally by the reference character, 5. Thecarburetor consists of a main body casting 6 which is adapted to besecured to the intake manifold 7 of the engine by bolts passing throughits flange, 8. The usual throttle valve 9 is provided to regulate thecharge to the intake manifold. Air is supplied to the induction passage10 thpough the air inlet pipe 11.

An air inlet valve 12, which is resiliently held upon its seat 13 byaspring 14, is arranged to control the admission of air from the inletpipe 11 to the induction` passage 10.

The degree of pressure exerted by the spring s.

be modified by adjusting the screw.

14 may plug 15 so as to change the initial compression of the spring 16,which is arranged to counteract the pressure of the larger spring 14.The dash pot piston 17, which `may be formed integral withthe stem ofthe valve 12, prevents fluttering of the valve. During the starting andordinary operation of the engine,

a considerable vacuum 1s developedin the induction passage 10, so thatthe atmospheric for governing the admission of the.

pressure upon the lower surfaceof the valve 12, will raise the valvefrom its seat to admit additional air from the air inlet 11.

The suction in the induction passage 10 is utilized to draw the fuelinto the carburetor as will now be described. A Venturi tube 19 isscrew-threaded into the wall of the induction passage and is open to theatmosphere, the nozzle of the tube projecting well within the inductionpassage. An annular fuel passage 20 surrounds the Venturi tube andcommunicates with its throat, which is slightly enlarged at this point,by ducts 21. The annular passage 20 is supplied with fuel through acanal 22 which terminates in a small chamber 18, surrounding the `stem23 of the fuel Valve 24. The valve 24 is adapted to rest upon a seat 25and the stem, 23, of this valve is screw-threaded into a ioat 26, whichis preferably made of a phenolic condensation product, such as theproduct known on the market as Bakelite The float, the valve and itsstem are freely reciprocable within a ioat chamber 27, and are guidedfor Vertical movement by the lowerv end 28 of the float, which isslidable in a suitable guide 29.

The chamber 18 communicates with the float chamber 27 through the smallannular passage the walls 0f the float chamber 27 are formed integralwith a downwardly projecting tube 31 which extends intothe mercury well32. The well 32 is formed by a jacket 33, which surrounds the walls ofthe ioat chamber and the tube 31. A flange 34 on the jacket 33 may besecured with a flange 35 of the float chamber to the body 6 in anysuitable manner. The bottom of the well 32, is formed by a cup-shapedmember 36, which is screwthreaded over the lower end of the jacket 33,and. isprovided with a vertically ribbed peripheral enlargement 37,which is engaged y a spring detent 38 secured to the jacket by means ofscrews 39. It will be apparent that by rotating the cup member 37 thelevel of the mercury within the Well 32 may be readily adjusted so as togovern the degree of vacuum necessary to open the valve 24.

A flaring` compartment 41, the lower portion of which forms the well 32,extends upsurrounding the valve stem 23, and.

wardly, surrounding the Walls of the float chamber 27. The upper end ofthis compartment communicates with a substantially annular trough 42through a plurality of vertically drilled holes 43. This trough is openat its upper edge, as shown at 44.

A cap 45 is secured over the top of this circular opening 44 by means ofa cap screw 46 which is threaded in the upper portion 47 of thecarburetor body. This cap screw has an axial duct 48 which communicateswith a diametrical assage 49 extending through the portion 4 It willthus be apparent that the space inside the cap 45 will be maintained atatmospheric pressure because of its communication with the atmospherethrough these passages 48 and 49. This cap construction and rathercircuitous passage for permitting air from the atmosphere to freelyenter into the compartment 41 is thus constructed to eliminate thepossibility of mercury leaking from the carburetor, should itaccidentally be tilted or be turned up side down. It will be apparentthat should the carburetor be inverted the mercury will merely rundownwardly through the passages 42, 43, 44 and will be caught within thecap 45. The quantity of mercury in the carburetor is not suiicient topermit it to pass through the ducts 48 and 49 even if all the mercuryshould drain to the inside of the cap 45. It will also be noted that thetop of the ioat chamber 27 i's dome shaped and that the wall surroundingthe small chamber 18 extends downwardly a suiiicient distance so thateven if the carburetor should be inverted the mercury could not escapethrough the port which surrounds the valve stem 23 and which connectsthe oat chamber with the chamber 18. Upon turning the carburetor back tonormal position, the mercury w1ll gravitate back into the well, 32. Nomatter how the carburetor is tilted, it will be imppssible to pour anyof the mercury from it, slnce the only passage to the atmosphere 1sthrough the ducts 48 and 49, and since, due to the peculiarconstruction, it is impossible for any of the mercury to escape throughthese passages. This is a very important feature since if, throughinadvertence or carelessness in handling, some of the mercury could bespilled from the carburetor this loss would entirely alter' thefunctioning of the carburetor and make it necessary to completelyreadjust it. l

Gasoline, or other liquid fuel, is supplied tothe carburetor by the pipe4, which terminates in the connection 51 screwed into the carburetorbody, and has a passage through the chamber 52, through the strainer 53,and through the ducts 54 into the central chamber 55 which liesimmediately above the valve 24. It will be apparent that the upper bodyportlon 47, may be unscrewed fnom the lower portion to permit theremoval of the filter screen or strainer 53, for cleaning.

lows:

Upon starting the engine, air is drawn through the Venturi tube 19 withgreat velocity. The rush of this air through the tube causes a vacuum atthe ports, or ducts 21, at the throat of the tube, which reducedpressure is communicated to the valve chamber 27, whereupon the mercurywill rise in the tube 31 until it surrounds the float 26 and raises itsufficiently to remove the valve 24 from its seat 25. Thereafter whenthe valve 24 is no longer seated, the reduced pressure is communicateddirectly to the chambers 55, 52 and connecting passages 54, so as todraw the gasoline or other liquid fuel from the suppl tank 3 thereto.Since the quantity of liqui fuel delivered for the proper functioning ofthe carburetor is dependent upon the dili'erence in pressures betweenvthe chambers 10 and 27, there will be a fixed quantity of fueldelivered to the carburetor venturi re,

gardless of the fuel lift existing between the main tank 3 andthechamber 27. This is true so long as the fuel lift does not exceed thedepression in chamber 27 and because the differential in pressurebetween the chambers 10 and 27 is maintained substantially constant bythe actuation of the float mechanism before described. Upon cessation ofthe operation ofthe engine, the valve 24 will seat and cut olf thegasoline supply line.

While the form of carburetor herein shown and described is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it was not intended to confine the invention to the one form ofembodiment herein disclosed, for it is susceptible of embodiment invarious forms, all coming within the scope of the claims which-follow.

I claim:

- 1. The combination of a low level tank with a carburetor having aninduction passage, means for utilizing the partial vacuum in saidpassage to draw liquid fuel from said low level tank, a float chamber, aiioat therein, a valve operatively connected to said float and adaptedto regulate the liow of the fuel from said low level supply tank to saidinduction passage, and a mercury well below said float chamber, themercury therein being adapted to buoy saidioat upwardly upon thereduction of pressure in said float chamber, that portion of the mercurybuoying the float being subjected to the partial vacuum of the inductionpassage and .the remaining portion being subjected to atmosphericpressure, and means for adjusting the level of the mercury in said well.l.

2. The combination of a low level tank with a carburetor having aninduction passage, means forutilizing the partial vacuum in said passageto draw liquid fuel from said low The operation of the carburetor Ais asfollevel tank, a float chamber, a float therein,a

valve operatively connected to said oat andI adapted to regulate theflow of the fuel from said low level supply tank to said inductionpassage, and a mercury well below said float chamber, the mercurytherein being adapted to buoy said float upwardly uponthe reduction ofpressure in said float chamber, that portion. of the mercury buoying thefloat being Vsubjected to the partial vacuum of the induction passageand thel remaining portion being subjected to atmospheric pressure.

3. In a carburetor, the combination of a float'chamber, a compartmentsurrounding said chamber, a oat movable in said chamber, a fuel inlet, avalve for regulating the admission of fuel secured to said oat, a'

vmunicating with the atmosphere 'point within the compartment, butspaced quantity of fluid .of high specific gravity.

adapted to buoy lsaid float upwardly and to open said valve upon apredetermined reduction of pressure in said float chamber, and means forpermitting the free admission of air at atmospheric pressure to saidcompartifnent, but preventing the escape of Huid thererom.

4. In a carburetor, means for supplying fuel to the carburetor includingthe combination of a float chamber, a compartment surfrom the wallsthereof so that the liquid will 70 not escape when the compartment' isinverted.

' In witness whereof, I hereunto subscribe my name this 9 day ofOctober, 1926.

' g CARL W. SPOHR.-

rounding said chamber, a float movable in l l 'said chamber, a quantityof mercury sealing the lowerend of said chamber in said compartment,said mercury being adapted to rise within said float chamber and buoysaid float upon a reduction of pressure in said float chamber, and ameans permitting the ingress of air to said compartment, butl preventingthe escape of mercury from the carburetor.

5. In a carburetor, means for supplying fuel to the carburetor includingthe combination 'of 'a float chamber, a compartment surrounding saidchamber, a well below said said chamber and compartment, wallsseparating said chamber from said compartment and terminatingv in a tube'extending into said well, a luid of high specific gravity 1n said well,a passage from the atmosphere to said compartment, said passagepermitting air to enter said compartment but preventing l the removal ofsaid fluid therefrom.

6. In a carburetor, means for vsupplying fuel to the carburetorincluding a' float cham# ber, a compartment surrounding said chamber,passages from` said compartment upwardly through said body, an invertedcupshaped member, closing the top of said compartment, and a assagecummunicating with the atmosphere 7 In a carburetor, means forvsupplying om a point Within said cu member but spaced from the wallsthereo

